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Gecko: Ouch 28 bars without shaft.... it was a "good" test for the UBL Piston indeed! A mares piston/shock absorber would have explosed !

Stamatis: My guns are Mares Sten 13 with differents vacuum kit (salvimar, pelengas and i used to have stc 1.0), the 2 with the salvimar kit (84 and 100 sten 13) are not noisier than that (it's not me on the video, but a french friend of mine):
I use them betwen 19 and 21 bar of pressure. My other gun (120 sten13) equiped with a pelengas kit is more silent even if i put about 22 bars of pressure.

The STC Kit or the sten without vacuum kit was much more noisier than with pelengas or Salvimar kit. I think bands guns are noisier than pneumatics guns with a salvimar or pelengas kit.

In order to check if your shock absorber or piston are OK, you have to empty your gun (beware! be sure it's really empty with and without the regulator on). Then, you unscrew the muzzle and check if the piston, the plastic part or the Orings of the shock absorbers are broken.

By the way: how can i edit a message on this forum? Sometimes my english is not good and i have to correct some words... but i didn't find how.

Member

Gecko: Ouch 28 bars without shaft.... it was a "good" test for the UBL Piston indeed! A mares piston/shock absorber would have explosed !

Stamatis: My guns are Mares Sten 13 with differents vacuum kit (salvimar, pelengas and i used to have stc 1.0), the 2 with the salvimar kit (84 and 100 sten 13) are not noisier than that (it's not me on the video, but a french friend of mine):
I use them betwen 19 and 21 bar of pressure. My other gun (120 sten13) equiped with a pelengas kit is more silent even if i put about 22 bars of pressure.

The STC Kit or the sten without vacuum kit was much more noisier than with pelengas or Salvimar kit. I think bands guns are noisier than pneumatics guns with a salvimar or pelengas kit.

In order to check if your shock absorber or piston are OK, you have to empty your gun (beware! be sure it's really empty with and without the regulator on). Then, you unscrew the muzzle and check if the piston, the plastic part or the Orings of the shock absorbers are broken.

By the way: how can i edit a message on this forum? Sometimes my english is not good and i have to correct some words... but i didn't find how.

Well-Known Member

Gecko: Ouch 28 bars without shaft.... it was a "good" test for the UBL Piston indeed! A mares piston/shock absorber would have explosed !

Stamatis: My guns are Mares Sten 13 with differents vacuum kit (salvimar, pelengas and i used to have stc 1.0), the 2 with the salvimar kit (84 and 100 sten 13) are not noisier than that (it's not me on the video, but a french friend of mine):
I use them betwen 19 and 21 bar of pressure. My other gun (120 sten13) equiped with a pelengas kit is more silent even if i put about 22 bars of pressure.

The STC Kit or the sten without vacuum kit was much more noisier than with pelengas or Salvimar kit. I think bands guns are noisier than pneumatics guns with a salvimar or pelengas kit.

In order to check if your shock absorber or piston are OK, you have to empty your gun (beware! be sure it's really empty with and without the regulator on). Then, you unscrew the muzzle and check if the piston, the plastic part or the Orings of the shock absorbers are broken.

By the way: how can i edit a message on this forum? Sometimes my english is not good and i have to correct some words... but i didn't find how.

Member

Gecko: Ouch 28 bars without shaft.... it was a "good" test for the UBL Piston indeed! A mares piston/shock absorber would have explosed !

Stamatis: My guns are Mares Sten 13 with differents vacuum kit (salvimar, pelengas and i used to have stc 1.0), the 2 with the salvimar kit (84 and 100 sten 13) are not noisier than that (it's not me on the video, but a french friend of mine):
I use them betwen 19 and 21 bar of pressure. My other gun (120 sten13) equiped with a pelengas kit is more silent even if i put about 22 bars of pressure.

The STC Kit or the sten without vacuum kit was much more noisier than with pelengas or Salvimar kit. I think bands guns are noisier than pneumatics guns with a salvimar or pelengas kit.

In order to check if your shock absorber or piston are OK, you have to empty your gun (beware! be sure it's really empty with and without the regulator on). Then, you unscrew the muzzle and check if the piston, the plastic part or the Orings of the shock absorbers are broken.

By the way: how can i edit a message on this forum? Sometimes my english is not good and i have to correct some words... but i didn't find how.

Well-Known Member

In regards to the race kit it's not really that racy. The trigger pin is the same dimension and though the length of the pull is in theory adjustable I am not sure how much you can practically change it before you run into issues with the line release. I don't know if there are any measurable performance increase from the pistons.

Member

In regards to the race kit it's not really that racy. The trigger pin is the same dimension and though the length of the pull is in theory adjustable I am not sure how much you can practically change it before you run into issues with the line release. I don't know if there are any measurable performance increase from the pistons.

Well, Edo from edoSub told me that the piston faster and better (more fluent, he said), but I wouldn't know if I don't measure it with a proper device. Sounds like a thing to do if and when one of these needs replacement.

Well-Known Member

Well, Edo from edoSub told me that the piston faster and better (more fluent, he said), but I wouldn't know if I don't measure it with a proper device. Sounds like a thing to do if and when one of these needs replacement.

I am not sure what that means! From your posting I conclude that a very good option is the Mares piston, right?
If I get this right, a piston is faster without that big rubber at the end, but you don't recoment removing it right?

Member

I am not sure what that means! From your posting I conclude that a very good option is the Mares piston, right?
If I get this right, a piston is faster without that big rubber at the end, but you don't recoment removing it right?

By the way, I know some people use suspention oil (for motorbikes) as lubricant. Is there a 'super' oil?
and since I am asking, I think Bobgun Pete mentioned that the oil sould be changed once a year, while the seals may never have to be replaced. What do you think?

Well-Known Member

Honestly, I can't really say which pistons are truly the best. And I don't think anyone has ever really tested it either. I know I broke two STC pistons, so I am off those. And just looking at the pics of the Salvimar Race Kit piston doesn't make it look like a big improvement over standard pistons, at least not to me. For my Mirages which run higher pressures, I trust the UBL setup. And for regular guns, I have just never had an issue with a standard 13mm Mares piston. From what I have read on Italian forums, they seem to be regarded as tough.

Now, I do like the idea of a lighter piston that is the shortest possible but one other big factor is, of course, the friction from the seals. Even changing the o-ring diameter and its compression across different designs will change this. But again, how much of a real life difference there is, I don't really know.
We have talked about static and dynamic friction before and if I understood it correctly, dynamic friction (e.g. a fast moving piston) is many, many times lower than static friction. The thing is, it is very hard to measure dynamic friction whereas you might be able to measure a slow moving piston which is closer to static friction (which I tried some years ago with a simple setup). I could measure a difference between a polished barrel and a standard one, but if the dynamic friction is many times lower it may not matter at all since the friction would be negligible anyways.
The only way I could see a test being done without the pressure target plate, that Omer likes to show off in some videos is by doing repeated penetration tests.

I did read somewhere (probably on an Italian forum) of some spearos removing the cup seal and I think if you are OK with taking your gun apart to check for salt water ingress after a few outings, I can, personally, not see any problem with that. If you find water behind the piston, you just dry everything out, regrease and reinstall the seal and you learned something. My gut feeling is that, in all likelihood, it would be safe. After all, STC, UBL, LGSub and Pelengas don't have cup seals. LGSub and Pelengas seem to even only have one regular o-ring and not two.

As for the oil, I just use a 7.5-10wt shock absorber oil. I end up changing it more than once a year since I have to take the guns apart every time I get in and out of China;-(.
A few years ago, I did stumble across some forums (guns and rifles stuff) debating high performance oils and greases. They talked a lot about adhesion properties - how one oil would stick to a part better than another oil - and so on, so there might actually be a super oil out there. I feel like I saved some links but can't find them now. Again, probably one of those things where it would be hard to quantify any performance increase.

Member

Honestly, I can't really say which pistons are truly the best. And I don't think anyone has ever really tested it either. I know I broke two STC pistons, so I am off those. And just looking at the pics of the Salvimar Race Kit piston doesn't make it look like a big improvement over standard pistons, at least not to me. For my Mirages which run higher pressures, I trust the UBL setup. And for regular guns, I have just never had an issue with a standard 13mm Mares piston. From what I have read on Italian forums, they seem to be regarded as tough.

Now, I do like the idea of a lighter piston that is the shortest possible but one other big factor is, of course, the friction from the seals. Even changing the o-ring diameter and its compression across different designs will change this. But again, how much of a real life difference there is, I don't really know.
We have talked about static and dynamic friction before and if I understood it correctly, dynamic friction (e.g. a fast moving piston) is many, many times lower than static friction. The thing is, it is very hard to measure dynamic friction whereas you might be able to measure a slow moving piston which is closer to static friction (which I tried some years ago with a simple setup). I could measure a difference between a polished barrel and a standard one, but if the dynamic friction is many times lower it may not matter at all since the friction would be negligible anyways.
The only way I could see a test being done without the pressure target plate, that Omer likes to show off in some videos is by doing repeated penetration tests.

I did read somewhere (probably on an Italian forum) of some spearos removing the cup seal and I think if you are OK with taking your gun apart to check for salt water ingress after a few outings, I can, personally, not see any problem with that. If you find water behind the piston, you just dry everything out, regrease and reinstall the seal and you learned something. My gut feeling is that, in all likelihood, it would be safe. After all, STC, UBL, LGSub and Pelengas don't have cup seals. LGSub and Pelengas seem to even only have one regular o-ring and not two.

As for the oil, I just use a 7.5-10wt shock absorber oil. I end up changing it more than once a year since I have to take the guns apart every time I get in and out of China;-(.
A few years ago, I did stumble across some forums (guns and rifles stuff) debating high performance oils and greases. They talked a lot about adhesion properties - how one oil would stick to a part better than another oil - and so on, so there might actually be a super oil out there. I feel like I saved some links but can't find them now. Again, probably one of those things where it would be hard to quantify any performance increase.

That's very thorough thanks!
Come to think of it, I read somewhere that some use some special gas instead of air, ever heard of that?
I am thinking, if one does dramatically increase the speed of the piston, what about the shock absorber? Isn't it likely it needs some tampering to increase their performance? What is that anyway? looks like a bunch of seals stacked together (I am talking about the salvimar). If they are, they are not included in the service collection.

Member

I think the shafts are basically the same for the all Salvimar models, provided their diameters match. The "Vuoto" aspect refers to the muzzle which has a seal that runs on the shaft, so the shaft diameter has to be right for that seal to work effectively. The "Predathor" is a redesign of the "Vintair" in order to provide a side mounted line release, hence the different rear handle shape. There are 7 mm and 8 mm diameter shafts, check the on-line Salvimar 2017 catalogue (pdf Acrobat file) to see which size your gun uses. In fact I just checked it and your 100 cm gun uses a 7 mm diameter shaft, the next two models up use 8 mm diameter shafts (115 cm and 130 cm). The other wet barrel "Vintair" and "Predathor" guns all use 8 mm shafts.

Hi I just purchased a Predathor Vuoto 65. I have the non vacuum version. I noticed that there is an O-ring on the shaft. Does it need to be positioned manually? It looks like something that would wear out quickly. There were no spares in the package, but only a spare seal for the muzzle. Should I buy some spares?
Also I noticed the Vuoto has no shaft spring like the regular Predathor. Is the shaft spring a necessary part for pneumatic spearguns?

Other differences is that the Vuoto comes with mono filament rather than spectra style line. Is it better?

I purchased a manometer, which is useful. Gun was shipped at 18 bar and pumped it to 22. I ordered the stuff from Spain and got everything within 2 weeks. Salvimar CS is hit or miss regarding email replies to inquiries.

Does the Vuoto need special care about rinsing / lubricating / storage compared to a regular muzzle?

But my main question is about the O ring. Not sure if I should have started a new thread, but this info can be useful to who's following this.

Member

Hi I just purchased a Predathor Vuoto 65. I have the non vacuum version. I noticed that there is an O-ring on the shaft. Does it need to be positioned manually? It looks like something that would wear out quickly. There were no spares in the package, but only a spare seal for the muzzle. Should I buy some spares?
Also I noticed the Vuoto has no shaft spring like the regular Predathor. Is the shaft spring a necessary part for pneumatic spearguns?

Other differences is that the Vuoto comes with mono filament rather than spectra style line. Is it better?

I purchased a manometer, which is useful. Gun was shipped at 18 bar and pumped it to 22. I ordered the stuff from Spain and got everything within 2 weeks. Salvimar CS is hit or miss regarding email replies to inquiries.

Does the Vuoto need special care about rinsing / lubricating / storage compared to a regular muzzle?

But my main question is about the O ring. Not sure if I should have started a new thread, but this info can be useful to who's following this.

I got a few muzzle seals when I bought the gun this fall. It's not wearing out so far (I have been fishing about 2-3 times a month). You just have to wash the gun thoroughly, especially the seal, and use a lubricant spray (I use silicon spray). I too have pumped it to 20atm approx. As for the o-ring on the shaft, if I understand correctly, it's the component that slides to the top of the muzzle and drives the shaft safely in and out. All pneumatics have that. My 100 doesn't have a spring either.

Member

I got a few muzzle seals when I bought the gun this fall. It's not wearing out so far (I have been fishing about 2-3 times a month). You just have to wash the gun thoroughly, especially the seal, and use a lubricant spray (I use silicon spray). I too have pumped it to 20atm approx. As for the o-ring on the shaft, if I understand correctly, it's the component that slides to the top of the muzzle and drives the shaft safely in and out. All pneumatics have that. My 100 doesn't have a spring either.

Thank you, for the O ring on the gasket, I do not mean the metal washer that all pneumatics have. There is a rubber / silicon tiny black O ring on the shaft, I wonder if I need to move it in a certain spot of the shaft. At parity of length and pressure, how does the Vuoto compare to a standard Predathor?

Member

Thank you, for the O ring on the gasket, I do not mean the metal washer that all pneumatics have. There is a rubber / silicon tiny black O ring on the shaft, I wonder if I need to move it in a certain spot of the shaft. At parity of length and pressure, how does the Vuoto compare to a standard Predathor?

Oh now I remember. It's supposed to hold the shaft's 'feather' I think, and repositiened for every shot. I lost it after a few shots. Not important.
I don't know how to answer the last part, as I have only shot a Syrano 85 (11mm)before that. I pumped it a full safe capacity (at least I tried). I was not happy at all with the power. I don't think I can compare it to my Vuoto 100, 'cause it has a total length of 110, so it's a tottaly different experience. I have to state again that I love that gun!

Member

I don't have a vuoto predathor, but for the comparison between regulars and spearguns with vacuum kit, here are the pros and cons to my point of view:
speargun with kit (vuoto predathor) is easier to load, more silent, lighter (no water in the barrel, just air), but vuoto is a litlle more complexe and need to be rinsed / lubricated, and you have to check the seal.

Personnally, With a vaccum kit, i just put less pressure in my spearguns: the fire range is not increased, but sill enough, and the loading is much more confortable. And i can keep my piston and shock absorber for a longger time.

Maybe, it would be better to take an 11mm barel if you don't want to add a vaccum kit. Spearguns like cyrano evo hf or cyrano 1.1, or even a sten 11mm, are very performant without kit.

Member

I don't have a vuoto predathor, but for the comparison between regulars and spearguns with vacuum kit, here are the pros and cons to my point of view:
speargun with kit (vuoto predathor) is easier to load, more silent, lighter (no water in the barrel, just air), but vuoto is a litlle more complexe and need to be rinsed / lubricated, and you have to check the seal.

Personnally, With a vaccum kit, i just put less pressure in my spearguns: the fire range is not increased, but sill enough, and the loading is much more confortable. And i can keep my piston and shock absorber for a longger time.

Maybe, it would be better to take an 11mm barel if you don't want to add a vaccum kit. Spearguns like cyrano evo hf or cyrano 1.1, or even a sten 11mm, are very performant without kit.

Thank you very clear. I had bought on sale last year a Salvimar Vintair plus 85 cm. It is a bit longer, not as well built. I wanted to know if the Predathor Vuoto 65 with the vacuum muzzle and thinner shaft may outperform it power / distance. It is also better for travel as it fits in my standard luggage.